Veneer lathes for peeling plywood veneer from a rotating log are well known. They include a pair of opposing rotatable chucks for rotating the log and a long blade held by a knife carriage for peeling the veneer from the log as it rotates. The log is rotated by a mechanism driven by an electric motor and, while the log is being peeled, the carriage is advanced slowly towards the log to peel a layer of required thickness. The mechanism for advancing the carriage towards the log while the log is being peeled is usually a mechanical mechanism coupled to the electric motor rotating the log. For example, some veneer lathes have a pair of spaced-apart threaded shafts extending away from the log through correspondingly tapped apertures in the knife carriage. The threaded shafts are rotated by a gear train connected to the electric motor to move the carriage towards the log. Of course, as the veneer is peeled from the log, the carriage moves closer to the centre of the log. Logs can be peeled effectively to a minimum core diameter of, for example, 51/4". This core must then be released from the chucks and a new log positioned. In order to position the new log, it is necessary to back the knife carriage away from the log. After the new log is properly positioned, the veneer carriage must be advanced towards the log until the knife contacts the log. The backing of the knife carriage away from the core and the advancing of the carriage towards the new log is preferably accomplished at a faster rate than the normal speed of advancement of the carriage while the log is being peeled. In the past, this rapid movement of the knife carriage was accomplished by driving the knife carriage with an electric motor. Approximately six to eight seconds were required to position a new log.
In the prior art, U.S. Pat. No. 2,027,295 to Stoddard employs a fluid cylinder for moving the knife.
U.S. Pat. No. 2,340,532 to Jackson employs a hydraulic cylinder for controlling the movement of the knife.
U.S. Pat. No. 3,244,206 to Bossen pertains to a device for monitoring moisture content to produce a uniform sheet of veneer.
U.S. Pat. No. 3,680,613 to Daniels shows a variable thickness control for a veneer lathe.